The policy decree, set to be unveiled tomorrow, is one of three long-awaited documents on detainee operations being formulated by the Pentagon, along with the still-pending Army Field Manual and a directive guiding interrogation practices.

Human rights activists have said US medical personnel have been complicit in detainee abuse, and have denounced force-feeding of prisoners as a violation of international codes of medical ethics.

The Pentagon said in a statement the new document "reaffirms the policy to prevent injury or loss of life of hunger strikers by involuntarily feeding those at serious risk of injury or death, as approved by the detention facility commanding officer or designated senior officer."

Many foreign terrorism suspects held at the US naval base at Guantanamo Bay, Cuba, have engaged in hunger strikes their lawyers call a protest of their conditions and lack of legal rights. The military has involuntarily fed some hunger strikers through tubes inserted through the nose and into the stomach.

Critics note that ethical codes endorsed by the American Medical Association, including a declaration by the World Medical Association, state that if a doctor considers a hunger striker "capable of forming an unimpaired and rational judgment concerning the consequences of such voluntary refusal of nourishment, he or she shall not be fed artificially."

Authorities at Guantanamo have said they have strapped some detainees into "restraint chairs" during involuntary feeding and isolated them after determining some had been purposely vomiting the liquid they had been fed. A senior general told reporters some detainees subsequently decided taking part in the hunger strike had become "too much of a hassle." Writing in March in the British medical journal The Lancet, 263 doctors from seven countries called on the United States to stop force-feeding detainees and using restraint chairs.

"It seems like the motive (for force-feeding detainees) is to prevent embarrassment to the United States government because they don't appear to be waiting until someone's life or health is in significant danger," said Leonard Rubenstein, executive director of the group Physicians for Human Rights.

Detainees' lawyers have previously accused the military of violently shoving tubes through the men's noses and into their stomachs without anesthesia or sedatives and then hurling religious taunts at them when they vomited blood.

Navy Cmdr. Robert Durand, a spokesman at Guantanamo, said this weekend the number of hunger strikers there had dropped from 89 as of last Thursday to 18.

"The hunger strike technique is consistent with al Qaeda practice and reflects detainee attempts to elicit media attention to bring international pressure on the United States to release them back to the battlefield," a military statement said.

The new policy directive also "reaffirms the responsibility of health care personnel to protect and treat all detainees under their care in keeping with the established principles of medical practice and humane treatment," the Pentagon said.

Pentagon guidelines do not prohibit medical personnel from assisting interrogations by using knowledge of a prisoner's medical or mental condition.